555

Could you clarify what you want with “555”? For example:

• math number theory (factorization, divisors, phi, etc.)
• binary/hex/Roman numeral representations
• something about a 555 timer circuit

If you’re after the math angle, here are quick facts:

• Prime factorization: 555 = 3 × 5 × 37
• Positive divisors: 1, 3, 5, 15, 37, 111, 185, 555
• Euler’s totient: φ(555) = 288
• Sum of divisors: σ(555) = 912
• Binary: 555 = 1000101011₂
• Hex: 555 = 0x22B
• Roman numeral: DLV

Want me to craft some practice problems (with solutions) on any of these? Or did you mean something else (e.g., 555 timer concepts)?